For Smartly Dressed Game's Unturned, I designed and modeled many skins and variants for the weapons in the game. Like with Counter-Strike: Global Offensive, I would publish my skins into the game's Steam Workshop and once there, they may be selected to be included into the game as official content. Out of the dozens of skins and custom meshes, 15 of them have been added to the game since April 2017.
See all of my selected/non-selected submissions here.
See my Unturned Workshop here. All weapon models are by Smartly Dressed Games unless noted by the "Custom Mesh" tag.